Azeotropic compositions of hfo-1234yf and propylene

ABSTRACT

Refrigerant compositions including 2,3,3,3-tetrafluoropropene (HFO-1234yf) and propylene (R-1270) which exhibit near-azeotropic or azeotrope-like behavior. The refrigerant compositions exhibit a low global warming potential (GWP) and are non-ozone depleting. The refrigerant compositions are useful as a heating or cooling fluids in a variety of heating or cooling systems including heat pumps and other heating and cooling loops, in for example the automotive industry.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application represents a national filing under 35 U.S.C. 371 ofInternational Application No. PCT/US2019/054181, filed Oct. 2, 2019 andclaims the benefit of U.S. Provisional Application No. 62/741,261, filedOct. 4, 2018, which is incorporated by reference herein in its entirety.

FIELD

The present invention is directed to azeotropic and near azeotropiccompositions of HFO-1234yf and propylene (R-290).

BACKGROUND

The automotive industry is going through an architecture platformrejuvenation from using an internal combustion engines (ICE) forpropulsion to using electric batteries for propulsion. This platformrejuvenation is severely limiting the size of the internal combustionengine (ICE) in hybrid, plug-in hybrid vehicles or possibly eliminatingthe ICE altogether in pure electric vehicles. Some vehicles stillmaintain an ICE and are noted as hybrid electric vehicle (HEV) orplug-in hybrids electric vehicle (PHEV) or mild hybrids electricvehicles (MHEV). Vehicles which are fully electric and have no ICE aredenoted as full electric vehicles (EVs). All HEV, PHEV, MHEV and EVs useat least one electric motor, where the electric motor provides some formof propulsion for the vehicles normally provided by the internalcombustion engine (ICE) found on gasoline/diesel powered vehicles.

In electrified vehicles, the ICE is typically reduced in size (HEV,PHEV, or MHEV) or eliminated (EV) to reduce vehicle weight therebyincreasing the electric drive-cycle. While the ICE's primary function isto provide vehicle propulsion, it also provides the necessary heat tothe passenger cabin as its secondary function. Typically, heating isrequired when ambient conditions are 10° C. or lower. In anon-electrified vehicle, there is excess heat from the ICE, which can bescavenged and used to heat the passenger cabin. It should be noted thatwhile the ICE may take some time to heat up and generate heat, itfunctions well to temperatures of −30° C. Therefore, in electrifiedvehicles, ICE size reduction or elimination is creating a demand forcost effective heating of the passenger cabin using a heat pump typefluid, i.e., a heat transfer fluid or working fluid which is capable ofbeing used in the heating and/or in the cooling mode as the needs of thepassenger cabin and battery management require heating and cooling.

Due to environmental pressures, the current automotive refrigerant,R-134a, a hydrofluorocarbon or HFC, is being phased out in favor oflower global warming potential (GWP) refrigerants with GWP <150. WhileHFO-1234yf, a hydrofluoro-olefin, meets the low GWP requirement (GWP=4per Pappadimitriou and GWP <1 per AR5), it has lower refrigerationcapacity and cannot fully meet the needs at low (−10° C.) to very low(−30° C.) ambient temperatures typically, without some type of systemalteration or working fluid change.

Similarly, the heating and cooling of stationary residential andcommercial structures also suffers from a lack of suitable low GWPrefrigerants to replace the older high GWP refrigerants currently inuse.

Due to the manner in which automotive vehicles are repaired or serviced,the fluid must have low or negligible glide. Currently, during thevehicle A/C repair or service process, refrigerant is handled throughspecific automotive service machines which recover the refrigerant,recycle the refrigerant to some intermittent quality level removinggross contaminants and then recharge the refrigerant back into thevehicle after repairs or servicing have been completed. These machinesare denoted as R/R/R machines since they recover, recycle, rechargerefrigerant. It is this on-site recovery, recycle and recharge ofrefrigerant during vehicle maintenance or repair, that low glide ispreferable and negligible glide most preferable. The current automotiveservice machines are not set-up to handle refrigerant with high glide orglide. Since the refrigerant is handled “on-site” at a vehicle repairshop, there is no opportunity to reconstitute a blend refrigerant to thecorrect composition such as is done at a refrigerant recycler.Refrigerants with higher glide can sometimes require “reconstitution” tothe original formulation otherwise there will be a loss in cycleperformance. Since a heat pump fluid would be handled in the same manneras the air-conditioning fluid, this requirement for low or no glidewould also apply for a heat pump type fluid as it would be handledand/or serviced in the same manner as the traditional air-conditioningfluids. Thus, there is a need for refrigerants which have low or noglide for automotive applications.

Therefore, there is a need for low GWP heat pump type fluids to meet theever-increasing needs of hybrid, mild hybrid, plug-in hybrid andelectric vehicles, electrified mass transport, and residential andcommercial structures for thermal management which can provide coolingand heating.

SUMMARY

The present invention relates to compositions of environmentallyfriendly refrigerant blends with ultra-low GWP, (GWP less than or equalto 10 GWP), low toxicity (class A per ANSI/ASHRAE standard 34 or ISOstandard 817), and low flammability (class 2L per ASHRAE 34 or ISO 817)for use in a hybrid, mild hybrid, plug-in hybrid, or full electricvehicles for thermal management (transferring heat from one part of thevehicle to the other) of the passenger compartment providing airconditioning (A/C) or heating to the passenger cabin. These refrigerantscan also be used for mass transport mobile applications which benefitfrom heat pump type heating and cooling of passenger cabin areas. Masstransport mobile applications are not limited to, but can includetransport vehicles such as ambulances, shuttles, buses and trains.

Compositions of the present invention exhibit low temperature glide overthe operating conditions of vehicle thermal management systems. In oneaspect of the invention, the refrigerant compositions include mixturesof HFO-1234yf and propylene exhibiting near-azeotropic behavior. Inanother aspect of the invention, the refrigerant compositions includemixtures of HFO-1234yf and propylene exhibiting azeotropic-likebehavior.

The present invention includes the following aspects and embodiments:

In one embodiment, disclosed herein are compositions useful asrefrigerants and heat transfer fluids. The compositions disclosed hereincomprise: 2,3,3,3-tetrafluoropropene (HFO-1234yf) and propylene(R-1270); wherein the composition is near-azeotropic.

According to any of the foregoing embodiments, also disclosed herein arecompositions wherein the composition is azeotrope-like.

According to any of the foregoing embodiments, also disclosed herein arecompositions wherein the 2,3,3,3-tetrafluoropropene (HFO-1234yf)concentration is greater than or equal to the 2,3,3,3-tetrafluoropropene(HFO-1234yf) concentration of a propylene NAL1; and wherein the2,3,3,3-tetrafluoropropene (HFO-1234yf) concentration is less than orequal to the 2,3,3,3-tetrafluoropropene (HFO-1234yf) concentration of apropylene NAH1.

According to any of the foregoing embodiments, also disclosed herein arecompositions wherein the 2,3,3,3-tetrafluoropropene (HFO-1234yf)concentration is greater than or equal to the 2,3,3,3-tetrafluoropropene(HFO-1234yf) concentration of a propylene ALL1; and wherein the2,3,3,3-tetrafluoropropene (HFO-1234yf) concentration is less than orequal to the 2,3,3,3-tetrafluoropropene (HFO-1234yf) concentration of apropylene ALH1.

According to any of the foregoing embodiments, also disclosed herein arecompositions wherein the propylene (R-1270) is present in an amount upto 24 weight percent, based on the total refrigerant composition.

According to any of the foregoing embodiments, also disclosed herein arecompositions wherein the propylene (R-1270) is from 1 to 20 weightpercent based on the total refrigerant composition.

According to any of the foregoing embodiments, also disclosed herein arecompositions wherein the propylene (R-1270) is present in an amount from1 to 10 weight percent based on the total refrigerant composition.

According to any of the foregoing embodiments, also disclosed herein arecompositions wherein the propylene (R-1270) is present in an amount from1 to 7 weight percent based on the total refrigerant composition.

According to any of the foregoing embodiments, also disclosed herein arecompositions wherein the composition exhibits near azeotropic propertiesover the temperature range of −30° C. to 40° C.

According to any of the foregoing embodiments, also disclosed herein arecompositions wherein the refrigerant composition is a heat pump fluid.

According to any of the foregoing embodiments, also disclosed herein arecompositions wherein the heat capacity of the refrigerant composition isbetween 2.9% and 27.5% greater than the heat capacity of2,3,3,3-tetrafluoropropene (HFO-1234yf) alone.

According to any of the foregoing embodiments, also disclosed herein arecompositions wherein the heat capacity of the refrigerant composition isbetween 2% and 22% greater than the heat capacity of2,3,3,3-tetrafluoropropene (HFO-1234yf) alone.

According to any of the foregoing embodiments, also disclosed herein arecompositions wherein the GWP of the refrigerant composition is less than10.

According to any of the foregoing embodiments, also disclosed herein arecompositions wherein the refrigerant composition has a temperature glideof less than 1.1 Kelvin (K) at temperature of −30° C. up to 10° C.

According to any of the foregoing embodiments, also disclosed herein arecompositions wherein a ratio of a heat capacity of the composition to aheat capacity of 2,3,3,3-tetrafluoropropene (HFO-1234yf) is between 1.05and 1.50 at the same temperature and pressure.

In another embodiment, disclosed herein a heating or cooling systemcomprising, in a serial arrangement: a condenser; an evaporator; and acompressor, the system further comprising each of the condenser,evaporator and compressor operably connected, the refrigerantcomposition of any of the foregoing embodiments being circulated througheach of the condenser, evaporator and compressor.

According to any of the foregoing embodiments, also disclosed herein areheating or cooling systems wherein the system is an air conditioner foran automotive system.

According to any of the foregoing embodiments, also disclosed herein areheating or cooling systems wherein the system is an air conditioner fora stationary cooling system.

According to any of the foregoing embodiments, also disclosed herein areheating or cooling systems further comprising a 4-way valve.

According to any of the foregoing embodiments, also disclosed herein areheating or cooling systems wherein the system is a heat pump for anautomotive system.

According to any of the foregoing embodiments, also disclosed herein areheating or cooling systems wherein the system is heat pump for aresidential heating or cooling system.

According to any of the foregoing embodiments, also disclosed herein areheating or cooling systems wherein a temperature glide is less than 1.1Kelvin (K).

According to any of the foregoing embodiments, also disclosed herein isthe use of the refrigerant composition of any of the foregoingembodiments in a heat pump system.

According to any of the foregoing embodiments, also disclosed herein isthe use of the refrigerant composition of any of the foregoingembodiments in an HEV, MHEV, PHEV, or EV heat pump system.

According to any of the foregoing embodiments, also disclosed herein isthe use of the refrigerant composition of any of the foregoingembodiments in an HEV, MHEV, PHEV, or EV heat pump system in combinationwith a vehicle electrical system.

According to any of the foregoing embodiments, also disclosed herein isa method of charging a refrigerant composition to an automotive systemthat includes providing the composition of any of the foregoingembodiments to an automotive heating or cooling system.

In another embodiment, disclosed herein a method for improving grosscontaminants from a refrigerant composition comprising: providing afirst refrigerant composition; wherein the first refrigerant compositionis not near azeotropic and includes 2,3,3,3-tetrafluoropropene(HFO-1234yf) and at least one of ethane (R-170) or propane (R-290);providing at least one of 2,3,3,3-tetrafluoropropene (HFO-1234yf),ethane (R-170) or propane (R-290) to the first refrigerant compositionto form a second refrigerant composition; wherein the second refrigerantcomposition is near-azeotropic.

According to any of the foregoing embodiments, also disclosed herein isa method wherein the second refrigerant composition is formed from thefirst refrigerant composition without the use of conventional onsiteautomatic recovery, recycle, recharge equipment.

Other features and advantages of the present invention will be apparentfrom the following more detailed description of the preferred embodimentwhich illustrates, by way of example, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the vapor/liquid equilibrium properties of blends ofHFO-1234yf and propylene, according to an embodiment.

FIG. 2 illustrates the vapor/liquid equilibrium properties of blends ofHFO-1234yf and propylene, according to an embodiment.

FIG. 3 illustrates a reversible cooling or heating loop system,according to an embodiment.

FIG. 4 illustrates a reversible cooling or heating loop system,according to an embodiment.

FIG. 5 illustrates a reversible cooling or heating loop system,according to an embodiment.

FIG. 6 illustrates a reversible cooling or heating loop system,according to an embodiment.

DETAILED DESCRIPTION Definitions

As used herein, the term heat transfer composition means a compositionused to carry heat from a heat source to a heat sink.

A heat source is defined as any space, location, object or body fromwhich it is desirable to add, transfer, move or remove heat. Example ofa heat source in this embodiment is the vehicle passenger compartmentrequiring air conditioning.

A heat sink is defined as any space, location, object or body capable ofabsorbing heat. An example of a heat sink in this embodiment is thevehicle passenger compartment requiring heating.

A heat transfer system is the system (or apparatus) used to produce aheating or cooling effect in a particular location. A heat transfersystem in this invention implies the reversible heating or coolingsystem which provides heating or cooling of the passenger cabin.Sometimes this system is called a heat pump system, reversible heatingloop, or reversible cooling loop.

A heat transfer fluid comprises at least one refrigerant and at leastone member selected from the group consisting of lubricants, stabilizersand flame suppressants.

Refrigeration capacity (also referred to as cooling or heating capacity,depending on which is the preferred requirement for the system) is aterm which defines the change in enthalpy of a refrigerant in anevaporator per kilogram of refrigerant circulated, or the heat removedby the refrigerant in the evaporator per unit volume of refrigerantvapor exiting the evaporator (volumetric capacity). The refrigerationcapacity is a measure of the ability of a refrigerant or heat transferfluid composition to produce cooling or heating Therefore, the higherthe capacity, the greater the cooling or heating that is produced.Cooling rate refers to the heat removed by the refrigerant in theevaporator per unit time. Heating rate refers to the heat removed by therefrigerant in the evaporator per unit time.

Coefficient of performance (COP) is the amount of heat removed dividedby the required energy input to operate the cycle. The higher the COP,the higher is the energy efficiency of the refrigerant or heat transferfluid. COP is directly related to the energy efficiency ratio (EER) thatis the efficiency rating for refrigeration or air conditioning equipmentat a specific set of internal and external temperatures.

Subcooling refers to the reduction of the temperature of a liquid belowthat liquid's saturation point for a given pressure. The liquidsaturation point is the temperature at which the vapor is completelycondensed to a liquid. Subcooling continues to cool the liquid to alower temperature liquid at the given pressure. By cooling a liquidbelow the saturation temperature (or bubble point temperature), the netrefrigeration capacity can be increased. Subcooling thereby improvesrefrigeration capacity and energy efficiency of a system. The subcoolamount is the amount of cooling below the saturation temperature (indegrees).

Superheating refers to the increase of the temperature of a vapor abovethat vapor's saturation point for a given pressure. The vapor saturationpoint is the temperature at which the liquid is completely evaporated toa vapor. Superheating continues to heat the vapor to a highertemperature vapor at a given pressure. By heating the vapor above thesaturation temperature (or dew point temperature), the net refrigerationcapacity can be increased. Superheating thereby improves refrigerationcapacity and energy efficiency of a system. The superheat amount is theamount of heating above the saturation temperature (in degrees).

Temperature glide (sometimes referred to simply as “glide”) is theabsolute value of the difference between the starting and endingtemperatures of a phase-change process by a refrigerant within a heatexchanger (evaporator or condenser) of a refrigerant system, exclusiveof any subcooling or superheating. This term may be used to describecondensation or evaporation of a near azeotrope or non-azeotropiccomposition. When referring to the temperature glide of an airconditioning or heat pump system, it is common to provide the averagetemperature glide being the average of the temperature glide in theevaporator and the temperature glide in the condenser. Glide isapplicable to blend refrigerants, i.e. refrigerants that are composed ofat least 2 components.

As used herein, the term low glide shall be understood as less than 3Kelvin (K) over the operating range of interest. In some embodiments,the glide may be than 2.5 K over operating range of interest or evenless than 0.75 K over operating range of interest.

By azeotropic composition is meant a constant-boiling mixture of two ormore substances that behave as a single substance. One way tocharacterize an azeotropic composition is that the vapor produced bypartial evaporation or distillation of the liquid has the samecomposition as the liquid from which it is evaporated or distilled,i.e., the mixture distills/refluxes without compositional change.Constant-boiling compositions are characterized as azeotropic becausethey exhibit either a maximum or minimum boiling point, as compared withthat of the non-azeotropic mixture of the same compounds. An azeotropiccomposition will not fractionate within an air conditioning or heatingsystem during operation. Additionally, an azeotropic composition willnot fractionate upon leakage from an air conditioning or heating system.

As used herein, the terms “near-azeotropic composition” shall beunderstood to mean a composition wherein the difference between thebubble point pressure (“BP”) and dew point pressure (“DP”) of thecomposition at a particular temperature is less than or equal to 5percent based upon the bubble point pressure, i.e., [(BP−DP)/BP]×100≤5.

As used herein, the term “azeotrope-like composition” shall beunderstood to mean a composition wherein the difference between thebubble point pressure (“BP”) and dew point pressure (“DP”) of thecomposition at a particular temperature is less than or equal to 3percent based upon the bubble point pressure, i.e., [(BP−DP)/BP]×100≤3.

As used herein, the term “first near-azeotropic low HFO-1234yfcomposition (NAL1)” shall be understood to mean the lowest concentrationof HFO-1234yf of a compositional range exhibiting near-azeotropicbehavior of an HFO-1234yf/propylene mixture.

As used herein, the term “first near-azeotropic high HFO-1234yfcomposition (NAH1)” shall be understood to mean the highestconcentration of HFO-1234yf of a compositional range exhibitingnear-azeotropic behavior of an HFO-1234yf/propylene mixture.

As used herein, the term “first azeotrope-like low HFO-1234yfcomposition (ALL1)” shall be understood to mean the lowest concentrationof HFO-1234yf of a compositional range exhibiting azeotrope-likebehavior of an HFO-1234yf/propylene mixture.

As used herein, the term “first azeotrope-like high HFO-1234yfcomposition (ALH1)” shall be understood to mean the highestconcentration of HFO-1234yf of a compositional range exhibitingazeotrope-like behavior of an HFO-1234yf/propylene mixture.

As used herein, the term “second near-azeotropic low HFO-1234yfcomposition (NAL2)” shall be understood to mean the lowest concentrationof HFO-1234yf of a compositional range exhibiting near-azeotropicbehavior of an HFO-1234yf/propylene mixture.

As used herein, the term “second near-azeotropic high HFO-1234yfcomposition (NAH2)” shall be understood to mean the highestconcentration of HFO-1234yf of a compositional range exhibitingnear-azeotropic behavior of an HFO-1234yf/propylene mixture.

As used herein, the term “second azeotrope-like low HFO-1234yfcomposition (ALL2)” shall be understood to mean the lowest concentrationof HFO-1234yf of a compositional range exhibiting azeotrope-likebehavior of an HFO-1234yf/propylene mixture.

As used herein, the term “second azeotrope-like high HFO-1234yfcomposition (ALH2)” shall be understood to mean the highestconcentration of HFO-1234yf of a compositional range exhibitingazeotrope-like behavior of an HFO-1234yf/propylene mixture.

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a composition,process, method, article, or apparatus that comprises a list of elementsis not necessarily limited to only those elements but may include otherelements not expressly listed or inherent to such composition, process,method, article, or apparatus. Further, unless expressly stated to thecontrary, “or” refers to an inclusive or and not to an exclusive or. Forexample, a condition A or B is satisfied by any one of the following: Ais true (or present) and B is false (or not present), A is false (or notpresent) and B is true (or present), and both A and B are true (orpresent).

The transitional phrase “consisting of” excludes any element, step, oringredient not specified. If in the claim such would close the claim tothe inclusion of materials other than those recited except forimpurities ordinarily associated therewith. When the phrase “consistsof” appears in a clause of the body of a claim, rather than immediatelyfollowing the preamble, it limits only the element set forth in thatclause; other elements are not excluded from the claim as a whole.

The transitional phrase “consisting essentially of” is used to define acomposition, method that includes materials, steps, features,components, or elements, in addition to those literally disclosedprovided that these additional included materials, steps, features,components, or elements do materially affect the basic and novelcharacteristic(s) of the claimed invention, especially the mode ofaction to achieve the desired result of any of the processes of thepresent invention. The term ‘consisting essentially of’ occupies amiddle ground between “comprising” and ‘consisting of’.

Where applicants have defined an invention or a portion thereof with anopen-ended term such as “comprising,” it should be readily understoodthat (unless otherwise stated) the description should be interpreted toalso include such an invention using the terms “consisting essentiallyof” or “consisting of.”

Also, use of “a” or “an” are employed to describe elements andcomponents described herein. This is done merely for convenience and togive a general sense of the scope of the invention. This descriptionshould be read to include one or at least one and the singular alsoincludes the plural unless it is obvious that it is meant otherwise.

Refrigerant Blend (Class A2, GWP <10 and 0 ODP)

Global warming potential (GWP) is an index for estimating relativeglobal warming contribution due to atmospheric emission of a kilogram ofa particular greenhouse gas compared to emission of a kilogram of carbondioxide. GWP can be calculated for different time horizons showing theeffect of atmospheric lifetime for a given gas. The GWP for the 100-yeartime horizon is commonly the value referenced in the industry and shallbe used herein. For fluid mixtures or refrigerant mixtures, a weightedaverage can be calculated based on the individual GWPs for eachcomponent. The United Nations Intergovernmental Panel on Climate Control(IPCC) provides vetted values for refrigerant GWPs in officialassessment reports (ARs.) The fourth assessment report is denoted as AR4and the fifth assessment report is denoted as AR5. Regulating bodes arecurrently using AR4 for official legislating purposes.

Ozone-depletion potential (ODP) is a number that refers to the amount ofozone depletion caused by a substance. The ODP is the ratio of theimpact on ozone of a chemical compared to the impact of a similar massof R-11 or fluorotrichloromethane. R-11 is a type of chlorofluorocarbon(CFC) and as such has chlorine in it which contributes to ozonedepletion. Furthermore, the ODP of CFC-11 is defined to be 1.0. OtherCFCs and hydrofluorochlorocarbons (HCFCs) have ODPs that range from 0.01to 1.0. Hydrocarbons (HC's) and the hydrofluoro-olefins (HFO's)described herein have zero ODP because they do not contain chlorine,bromine or iodine, species known to contribute to ozone breakdown anddepletion. Hydrocarbons (HC's) also do not have ODP as they bydefinition also do not contain chlorine, bromine or iodine.

The refrigerant blend compositions comprise at least onehydrofluoro-olefin such as 2,3,3,3-tetrafluoropropene (HFO-1234yf) andat least one hydrocarbon such as propylene (R-1270).

The unsaturated hydrofluoro-olefin (HFO) refrigerant components alsohave very low GWP, with all HFO components having GWP <10. Thehydrocarbon (HC) refrigerant component includes propylene. The HCcomponent also has a very low GWP. For example, propylene has a GWP of2.

Therefore, the final blends have 0 ODP and ultra-low GWP, or GWP <10.Table 1, shown below, is a summary table showing type, ODP and GWP perthe 4^(th) and the 5^(th) assessment conducted by the IntergovernmentalPanel on Climate Control (IPCC) for 2,3,3,3-tetrafluoropropene(HFO-1234yf), and various combinations thereof.

For the blend, GWP may be calculated as a weighted average of theindividual GWP values in the blend, taking into account the amount(e.g., weight %) of each ingredient (1-n) in the blend, as shown inEquation (1) below.

GWP Blend=Amount1 (GWP of component 1) +Amount2 (GWP component 2)+Amountn (GWP of component n)   Equation (1):

TABLE 1 Refrigerant GWP AR4 GWP AR5 Refrigerant Type ODP (IPCC) (IPCC)R-12 CFC 1 10900 10200 R-134a HFC 0 1430 1300 R-1234yf HFO 0 4 1 R-1270HC 0 2 2 R-1234yf/R-1270 HFO/HC 0 4.0 1.0 (99 wt %/1 wt %)R-1234yf/R-1270 HFO/HC 0 3.9 1.1 (95 wt %/5 wt %) R-1234yf/R-1270 HFO/HC0 3.7 1.1 (90 wt %/10 wt %) R-1234yf/R-1270 HFO/HC 0 3.5 1.3 (76.2 wt%/23.8 wt %)

Resultant GWP for several blends of interest for HFO-1234yf and R-1270are noted below. Blends with R-1270 were limited to 23.8 wt % so thatthe resultant blend would meet the ASHRAE class 2 flammabilityrequirements. Due to the ultra-low GWPs of both HFO-1234yf and R-1270,blends which contain up to 23.8 wt % of R-1270 will have final GWP lessthan 5 based on IPCC AR4 and even lower than GWP of 2 based on IPCC AR5.

Refrigerant Lubricant

The refrigerant or heat transfer compositions of the present inventioncan be mixed with a lubricant and used as a “complete working fluidcomposition” of the present invention. The refrigerant composition ofthe present invention containing the heat transfer or working fluid ofthe present invention and the lubricant may contain publicly knownadditives such as a stabilizer, a leakage detection material, and otherbeneficial additives. It is also possible for the lubricant to impactthe flammability level of the resulting compound.

The lubricant chosen for this composition preferably has sufficientsolubility in the vehicle's A/C refrigerant to ensure that the lubricantcan return to the compressor from the evaporator. Furthermore, thelubricant preferably has a relatively low viscosity at low temperaturesso that the lubricant is able to pass through the cold evaporator. Inone preferred embodiment, the lubricant and A/C refrigerant are miscibleover a broad range of temperatures.

Preferred lubricants may be one or more polyol ester type lubricants.(POEs). Polyol ester as used herein include compounds containing anester of a diol or a polyol having from about 3 to 20 hydroxyl groupsand a fatty acid having from about 1 to 24 carbon atoms is preferablyused as the polyol. An ester which can be used as the base oil.(EUROPEAN PATENT APPLICATION published in accordance with Art. 153(4) EP2 727 980 A1, which is hereby incorporated by reference). Here, examplesof the diol include ethylene glycol, 1,3-propanediol, propylene glycol,1,4-butanediol, 1,2-butanediol, 2-methyl-1,3-propanediol,1,5-pentanediol, neopentyl glycol, 1,6-hexanediol,2-ethyl-2-methyl-1,3-propanediol, 1,7-heptanediol,2-methyl-2-propyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol,1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol,1,12-dodecanediol, and the like.

Examples of the above-described polyol include a polyhydric alcohol suchas trimethylolethane, trimethylolpropane, trimethylolbutane,di(trimethylolpropane), tri(trimethylolpropane), pentaerythritol,di(pentaerythritol), tri(pentaerythritol), glycerin, polyglycerin (dimerto eicosamer of glycerin), 1,3,5-pentanetriol, sorbitol, sorbitan, asorbitol-glycerin condensate, adonitol, arabitol, xylitol, mannitol,etc.; a saccharide such as xylose, arabinose, ribose, rhamnose, glucose,fructose, galactose, mannose, sorbose, cellobiose, maltose, isomaltose,trehalose, sucrose, raffinose, gentianose, melezitose, etc.; partiallyetherified products and methyl glucosides thereof; and the like. Amongthese, a hindered alcohol such as neopentyl glycol, trimethylolethane,trimethylolpropane, trimethylolbutane, di(trimethylolpropane),tri(trimethylolpropane), pentaerythritol, or di(pentaerythritol),tri(pentaerythritol) is preferable as the polyol.

Though the fatty acid is not particularly limited on its carbon number,in general, a fatty acid having from 1 to 24 carbon atoms is used. Inthe fatty acid having from 1 to 24 carbon atoms, a fatty acid having 3or more carbon atoms is preferable, a fatty acid having 4 or more carbonatoms is more preferable, a fatty acid having 5 or more carbon atoms isstill more preferable, and a fatty acid having 10 or more carbon atomsis the most preferable from the standpoint of lubricating properties. Inaddition, a fatty acid having not more than 18 carbon atoms ispreferable, a fatty acid having not more than 12 carbon atoms is morepreferable, and a fatty acid having not more than 9 carbon atoms isstill more preferable from the standpoint of compatibility with therefrigerant.

In addition, the fatty acid may be either of a linear fatty acid and abranched fatty acid, and the fatty acid is preferably a linear fattyacid from the standpoint of lubricating properties, whereas it ispreferably a branched fatty acid from the standpoint of hydrolysisstability. Furthermore, the fatty acid may be either of a saturatedfatty acid and an unsaturated fatty acid. Specifically, examples of theabove-described fatty acid include a linear or branched fatty acid suchas pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid,nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid,tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoicacid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid,icosanoic acid, oleic acid, etc.; a so-called neo acid in which acarboxylic group is attached to a quaternary carbon atom; and the like.More specifically, preferred examples thereof include valeric acid(n-pentanoic acid), caproic acid (n-hexanoicacid), enanthic acid(n-heptanoic acid), caprylic acid (n-octanoic acid), pelargonic acid(n-nonanoic acid), capric acid (n-decanoic acid), oleic acid(cis-9-octadecenoic acid), isopentanoic acid (3-methylbutanoic acid),2-methylhexanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid,3,5,5-trimethylhexanoic acid, and the like. Incidentally, the polyolester maybe a partial ester in which the hydroxyl groups of the polyolremain without being fully esterified; a complete ester in which all ofthe hydroxyl groups are esterified; or a mixture of a partial ester anda complete ester, with a complete ester being preferable.

In the polyol ester, an ester of a hindered alcohol such as neopentylglycol, trimethylolethane, trimethylolpropane, trimethylolbutane,di(trimethylolpropane), tri(trimethylolpropane), pentaerythritol,di(pentaerythritol), tri(pentaerythritol), etc. is more preferable, withan ester of neopentyl glycol, trimethylolethane, trimethylolpropane,trimethylolbutane, or pentaerythritol being still more preferable, fromthe standpoint of more excellent hydrolysis stability; and an ester ofpentaerythritol is the most preferable from the standpoint of especiallyexcellent compatibility with the refrigerant and hydrolysis stability.

Preferred specific examples of the polyol ester include a diester ofneopentyl glycol with one kind or two or more kinds of fatty acidsselected from valeric acid, caproic acid, enanthic acid, caprylic acid,pelargonic acid, capric acid, oleic acid, isopentanoic acid,2-methylhexanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid, and3,5,5-trimethylhexanoic acid; a triester of trimethylolethane with onekind or two or more kinds of fatty acids selected from valeric acid,caproic acid, enanthic acid, caprylic acid, pelargonic acid, capricacid, oleic acid, isopentanoic acid, 2-methylhexanoic acid,2-ethylpentanoic acid, 2-ethylhexanoic acid, and 3,5,5-trimethylhexanoicacid; a triester of trimethylolpropane with one kind or two or morekinds of fatty acids selected from valeric acid, caproic acid, enanthicacid, caprylic acid, pelargonic acid, capric acid, oleic acid,isopentanoic acid, 2-methylhexanoic acid, 2-ethylpentanoic acid,2-ethylhexanoic acid, and 3, 5, 5-trimethylhexanoic acid; a triester oftrimethylolbutane with one kind or two or more kinds of fatty acidsselected from valeric acid, caproic acid, enanthic acid, caprylic acid,pelargonic acid, capric acid, oleic acid, isopentanoic acid,2-methylhexanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid, and3,5,5-trimethylhexanoic acid; and a tetraester of pentaerythritol withone kind or two or more kinds of fatty acids selected from valeric acid,caproic acid, enanthic acid, caprylic acid, pelargonic acid, capricacid, oleic acid, isopentanoic acid, 2-methylhexanoic acid,2-ethylpentanoic acid, 2-ethylhexanoic acid, and 3,5,5-trimethylhexanoicacid. Incidentally, the ester with two or more kinds of fatty acids maybe a mixture of two or more kinds of esters of one kind of a fatty acidand a polyol, and an ester of a mixed fatty acid of two or more kindsthereof and a polyol, particularly an ester of a mixed fatty acid and apolyol is excellent in low-temperature properties and compatibility withthe refrigerant.

In a preferred embodiment, the lubricant is soluble in the refrigerantat temperatures between about −35° C. and about 100° C., and morepreferably in the range of about −30° C. and about 40° C., and even morespecifically between −25° C. and 40° C. In another embodiment,attempting to maintain the lubricant in the compressor is not a priorityand thus high temperature insolubility is not preferred.

The lubricant used for electrified automotive air-conditioningapplication may have a kinematic viscosity (measured at 40° C.,according to ASTM D445) between 75-110 cSt, and ideally about 80 cSt-100cSt and most specifically, between 85 cst-95 cSt. However, not wantingto limit the invention, it should be noted that other lubricantviscosities may be used depending on the needs of the electrifiedvehicle A/C compressor.

To suppress the hydrolysis of the lubricating oil, it is necessary tocontrol the moisture concentration in the heating/cooling system forelectric type vehicles. Therefore, the lubricant in this embodimentneeds to have low moisture, typically less than 100 ppm by weight.

Refrigerant Stabilizers

HFO type refrigerants, due to the presence of a double bond, may besubject to thermal instability and decompose under extreme use, handlingor storage situations. Therefore, there may be advantages to addingstabilizers to HFO type refrigerants. Stabilizers may notably includenitromethane, ascorbic acid, terephthalic acid, azoles such astolutriazole or benzotriazole, phenolic compounds such as tocopherol,hydroquinone, t-butyl hydroquinone, 2,6-di-tertbutyl-4-methylphenol,epoxides (possibly fluorated or perfluorated alkyl epoxides or alkenylor aromatic epoxides) such as n-butyl glycidyl ether, hexanedioldiglycidyl ether, allyl glycidyl ether, butylphenylglycidyl ether,terpenes, such as d-limonene or alpha and beta-pinene, phosphites,phosphates, phosphonates, thiols and lactones.

Not wanting to be prescriptive, blends may or may not includestabilizers depending on the requirements of the system being used. Ifthe refrigerant blend does include a stabilizer, it may include anyamount from 0.01 weight percent up to 1 weight percent of any of thestabilizers listed above, but most preferably tocopherol, or d-limonene.

Refrigerant Blend Flammability

Flammability is a term used to mean the ability of a composition toignite and/or propagate a flame. For refrigerants and other heattransfer compositions or working fluids, the lower flammability limit(“LFL”) is the minimum concentration of the heat transfer composition inair that is capable of propagating a flame through a homogeneous mixtureof the composition and air under test conditions specified in ASTM(American Society of Testing and Materials) E681. The upper flammabilitylimit (“UFL”) is the maximum concentration of the heat transfercomposition in air that is capable of propagating a flame through ahomogeneous mixture of the composition and air under the same testconditions.

In order to be classified by ANSI/ASHRAE (American Society of Heating,Refrigerating and Air-Conditioning Engineers) as (class 1, no flamepropagation), a refrigerant must meet the conditions of ASTM E681 asformulated in both the liquid and vapor phase as well as non-flammablein both the liquid and vapor phases that result during leakagescenarios.

In order for a refrigerant to be classified by ANSI/ASHRAE (AmericanSociety of Heating, Refrigerating and Air-Conditioning Engineers) as lowflammability (class 2L), the refrigerant: 1) exhibits flame propagationwhen tested at 140° F. (60° C.) and 14.7 psia (101.3 kPa), 2) has anLFL >0.0062 lb/ft³ (0.10 kg/m3), 3) a maximum burning velocity of ≤3.9in./s (10 cm/s) when tested at 73.4° F. (23.0° C.) and 14.7 psia (101.3kPa). and 4) has a heat of combustion <8169 Btu/lb (19,000 kJ/kg).2,3,3,3-tetrafluoropropene (HFO-1234yf) has ANSI/ASHRAE standard 34class 2L flammability rating.

In order for a refrigerant to be classified by ANSI/ASHRAE Standard 34class 2, the refrigerant 1) exhibits flame propagation when tested at140° F. (60° C.) and 14.7 psia (101.3 kPa), 2) has an LFL >0.0062 lb/ft³(0.10 kg/m³) and 3) has a heat of combustion <8169 Btu/lb (19,000kJ/kg).

In order for a refrigerant to be classified by ANSI/ASHRAE standard 34class 3, refrigerant 1) exhibits flame propagation when tested at 140°F. (60° C.) and 14.7 psia (101.3 kPa), 2) has an LFL <0.0062 lb/ft³(0.10 kg/m³) or 3) has a heat of combustion >8169 Btu/lb (19,000 kJ/kg).

When the HFO component and the HC components are blended together in thecorrect proportions, the resulting blend has class 2 flammability asdefined by ANSI/ASHRAE standard 34 and ISO 817. Class 2 flammability isinherently less flammable (i.e., lower energy release as exemplified bythe Heat of Combustion or HOC value) than class 3 flammability and canbe managed in automotive heating/cooling systems.

ASHRAE Standard 34 provides a methodology to calculate the heat ofcombustion for refrigerant blends using a balanced stoichiometricequation based on the complete combustion of one mole of refrigerantwith enough oxygen for a stoichiometric reaction.

It can be seen from the table below that based on the heat of combustioncalculation provided in ASHRAE Standard 34 section 6.1.3.6, it ispossible to have from 0.1 wt % to 23.8 wt % of propylene combined withHFO-1234yf and still meet the heat of combustion requirements for ASHRAEclass 2 flammability (HOC <19 KJ/kg.)

TABLE 2 Toxicity Class per Heat of ASHRAE ASHRAE Combustion[HOC] Std 3434 or (KJ/kg) estimated Flammability estimated per ASHRAE Std Classbased Refrigerants from TLV 34 Method on HOC R-1234yf A 10.7 2 L R-1270A 43.8 3 R-1234yf/R-1270 A 11.1 2 (99 wt %/1 wt %) R-1234yf/R-1270 A12.6 2 (95 wt %/5 wt %) R-1234yf/R-1270 A 14.4 2 (90 wt %/10 wt %)R-1234yf/R-1270 A 19.0 2 (76.2 wt %/23.8 wt %)

When the HFO component and the HC components are blended together ineven more precise proportions, the resulting blend has class 2Lflammability as defined by ANSI/ASHRAE standard 34 and ISO 817. Class 2Lflammability is inherently much less flammable (i.e., lower energyrelease as exemplified by the Heat of Combustion or HOC value) thanclass 3 flammability and can be managed in automotive heating/coolingsystems.

TABLE 3 Toxicity Heat of ASHRAE Class per Combustion[HOC] Std 34 ASHRAE34 or LFL (vol %) (KJ/kg) estimated Flammability estimated per ASTM LFLper ASHRAE Std Class based Refrigerants from TLV E681 (kg/m3) 34 Methodon HOC HFO-1234yf A 6.2 0.289 10.7 2 L R-1270 A 2.1 0.047 46.4 3R-1234yf/R-1270 A 4.75 0.204 12.8 2 (95 wt %/5 wt %)

It is also possible to blend the HFO component and HC component and adda flame suppressant such that the resulting blend has class 2Lflammability as defined by ANSI/ASHRAE standard 34 and ISO 817. Class 2Lflammability is inherently much less flammable (i.e., lower energyrelease as exemplified by the Heat of Combustion or HOC value) thanclass 3 flammability and can be managed in automotive heating/coolingsystems. An example of this is adding CF3I or other known flamesuppressant such that the refrigerant blend properties are not impactedand the resultant blend is class 2L flammable. It is even possible toadd enough flame suppressant to reduce the flammability such theresultant blend is class 1 and does not exhibit flame propagation.

The toxicity of these components has also been reviewed by WEEL orsimilar toxicological type committee and found to have toxicity valuesgreater than 400 ppm and therefore classified by ANSI/ASHRAE standard 34and ISO 817 as class A or low toxicity level.

Compositions of the present invention azeotrope-like and/ornear-azeotropic properties over temperature ranges desirably employed inthermal management systems. Azeotrope-like and/or near-azeotropiccompositions exhibit low temperature glide when used in thermalmanagement systems, such as refrigeration or air conditioning systems.In some embodiments, the compositions exhibit azeotrope-like and/ornear-azeotropic properties at both the desired evaporator and condenseroperating temperatures.

Mixtures of HFO-1234yf and propylene may exhibit azeotrope-like and/ornear-azeotropic properties over one or more concentration rangesdepending on the temperature and pressure. In some embodiments, arefrigerant composition of HFO-1234yf and propylene may exhibitnear-azeotropic properties over a range of concentrations from apropylene NAL1 to a propylene NAH1. In some embodiments, a refrigerantcomposition of HFO-1234yf and propylene may exhibit azeotrope-likeand/or near-azeotropic properties over a range of concentrations from apropylene NAL2 to a propylene NAH2. In some embodiments, a propyleneNAL1 to a propylene NAH1 and a propylene NAL2 to a propylene NAH2 rangesoverlap.

It will also be understood that inventive compositions exhibitingnear-azeotropic properties may possess HFO-1234yf concentrations as partof the HFO-1234yf/propylene compositions between the HFO-1234yfconcentration corresponding to a propylene NAL1 and the HFO-1234yfconcentration corresponding to a propylene NAH1. Similarly, thecompositions associated with a propylene NAL2, a propylene NAH2, and thecompositions exhibiting near-azeotropic having HFO-1234yf concentrationsbetween a propylene NAL2 and a propylene NAH2 may be as described above.

In some embodiments, a refrigerant composition of HFO-1234yf andpropylene may exhibit azeotrope-like properties over a range ofconcentrations from a propylene ALL1 to a propylene ALH1. In someembodiments, a refrigerant composition of HFO-1234yf and propylene mayexhibit azeotrope-like and/or near-azeotropic properties over a range ofconcentrations from a propylene ALL2 to a propylene ALH2. In someembodiments, a propylene ALL1 to a propylene ALH1 and a propylene ALL2to a propylene ALH2 ranges overlap.

It will also be understood that inventive compositions exhibitingnear-azeotropic properties may possess HFO-1234yf concentrations as partof the HFO-1234yf/propylene compositions between the HFO-1234yfconcentration corresponding to a propylene AAL1 and the HFO-1234yfconcentration corresponding to a propylene AAH1. Similarly, thecompositions associated with a propylene AAL2, a propylene AAH2, and thecompositions exhibiting near-azeotropic having HFO-1234yf concentrationsbetween a propylene AAL2 and a propylene AAH2 may be as described above.

One aspect of the invention is shown in FIG. 1. In the example of FIG.1, the percent deviation between bubble point and dew point pressurebased on bubble point pressure of R-1234yf/Propylene at 0° C. isillustrated. The system is a near azeotrope from a propylene NAL1 (610)of 0 to a propylene NAH1 (650) of about 60.4 weight percent R-1234yf and100 to about 39.6 weight percent propylene at a temperature of about 0°C. The system is also near azeotropic from a propylene NAL2 (660) ofabout 98.4 to a propylene NAH2 (640) of 100 weight percent R-1234yf andabout 1.6 to 0 weight percent propylene at a temperature of about 0° C.

The system is an azeotrope-like from and a propylene ALL1 (615) of 0 toa propylene ALH1 (620) of about 54.2 weight percent R-1234yf and 100 toabout 45.8 weight percent propylene at a temperature of about 0° C. Thesystem is also azeotrope-like from a propylene ALL2 (630) of about 99.1to a propylene ALH2 (645) of 100 weight percent R-1234yf and about 0.9to 0 weight percent propylene at a temperature of about 0° C.

Another aspect of the invention is shown in FIG. 2. In the example ofFIG. 2, the percent deviation between bubble point and dew pointpressure based on bubble point pressure of R-1234yf/Propylene at 40° C.is illustrated. The system is a near azeotrope from a propylene NAL1(610) about 0 to a propylene NAH1 (650) of about 72.3 weight percentR-1234yf and about 100 to about 27.7 weight percent propylene at atemperature of about 40° C. The system is also a near azeotrope from apropylene NAL2 (660) of about 96.4 to a propylene NAH2 (640) of 100weight percent R-1234yf and about 3.6 to 0 weight percent propylene at atemperature of about 40° C.

The system is azeotrope-like from a propylene ALL1 (615) of 0 to apropylene ALH1 (620) of about 64.4 weight percent R-1234yf and 100 toabout 35.6 weight percent propylene at a temperature of about 40 degreesCelsius. The system is also azeotrope-like from a propylene ALL2 (630)of about 98.2 to a propylene ALH2 (645) of 100 weight percent R-1234yfand about 1.8 to 0 weight percent propylene at a temperature of about 40degrees Celsius.

This system as an azeotrope that ranges from about 21.5 to 26.1 weightpercent R-1234yf and about 78.5 to about 73.9 weight percent propyleneover the temperature range of at least 0 to 40° C.

In embodiments, the refrigerant blends include2,3,3,3-tetrafluoropropene (HFO-1234yf) and propylene (R-290). In someembodiments, the refrigerant blends may consist of2,3,3,3-tetrafluoropropene (HFO-1234yf) and propylene (R-290). In someembodiments, the refrigerant blends may comprise blends ranging from 1weight percent propylene to 10 weight percent propylene. Morespecifically, the blend may contain from 5 weight percent to 10 weightpercent propylene and even more specifically from 5 weight percent to 7weight percent of propylene.

While HFO-1234yf can be used as an air-conditioning refrigerant, it islimited in its ability to perform as a heat pump type fluid, i.e. incooling and heating mode or in a reversible cycle system. Therefore, therefrigerants noted herein uniquely provide improved capacity overHFO-1234yf in the heating operating range, extend the lower heatingrange capability over HFO-1234yf to −30° C., have extremely low GWP andlow to mild flammability, while also uniquely exhibiting low or nearlynegligible glide. Hence these refrigerants are most useful inelectrified vehicle applications, particularly HEV, PHEV, MHEV, EV andmass transport vehicles which require these properties over the lowerend heating range. It should also be noted that any heat pump type fluidalso needs to perform well in the air-conditioning range, i.e. up to 40°C., providing increased capacity versus HFO-1234yf. Therefore, therefrigerant blends noted herein perform well over a range oftemperatures, particularly from −30° C. up to +40° C. and can provideheating and/or cooling depending upon which cycle they are being used inthe heat pump system.

The refrigerant blends may be used in a variety of heating and coolingsystems. In the embodiment of FIG. 3, a refrigeration system 100 havinga refrigeration loop 110 comprises a first heat exchanger 120, apressure regulator 130, a second heat exchanger 140, a compressor 150and a four-way valve 160. The first and second heat exchangers are ofthe air/refrigerant type. The first heat exchanger 120 has passingthrough it the refrigerant of the loop 110 and the stream of air createdby a fan. All or some of this same air stream may also pass through aheat exchanger an external cooling circuit, such as an engine (notdepicted in FIG. 3). Likewise, the second heat exchanger 140 has passingthrough it an air stream created by a fan. All or some of this airstream may also pass through another external cooling circuit (notdepicted in FIG. 3). The direction in which the air flows is dependenton the mode of operation of the loop 110 and on the requirements of theexternal cooling circuit. Thus, in the case of an engine, when theengine is idle and the loop 110 is in heat pump mode, the air can beheated up by the heat exchanger of the engine cooling circuit and thenblown onto the heat exchanger 120 to speed up the evaporation of thefluid of the loop 110 and thus improve the performance of this loop. Theheat exchangers of the cooling circuit may be activated by valvesaccording to engine requirements, such as, heating of the air enteringthe engine or putting the energy produced by this engine to productiveuse.

In refrigeration mode, the refrigerant set in motion by the compressor150 passes, via the valve 160, through the heat exchanger 120 which actsas a condenser, that is to say gives up heat energy to the outside, thenthrough the pressure regulator 130 then through the heat exchanger 140that is acting as an evaporator thus cooling the stream of air intendedto be blown into the motor vehicle cabin interior.

In heat pump mode, the direction of flow of the refrigerant is reversedusing the valve 160. The heat exchanger 140 acts as a condenser whilethe heat exchanger 120 acts as an evaporator. The heat exchanger 140 canthen be used to heat up the stream of air intended for the motor vehiclecabin.

In the embodiment of FIG. 4, a refrigeration system 200 having arefrigeration loop 210 comprises a first heat exchanger 220, a pressureregulator 230, a second heat exchanger 240, a compressor 250, a four-wayvalve 260, and a branch-off 270 mounted, on the one hand, at the exit ofthe heat exchanger 220 and, on the other hand, at the exit of the heatexchanger 240 when considering the direction of flow of the fluid inrefrigeration mode. This branch comprises a heat exchanger 280 throughwhich there passes a stream of air or stream of exhaust gas which isintended to be admitted to the engine and a pressure regulator 280. Thefirst and second heat exchangers 220 and 240 are of the air/refrigeranttype. The first heat exchanger 220 has passing through it therefrigerant from the loop 210 and the stream of air introduced by a fan.All or some of this same air stream also passes through a heat exchangerof the engine cooling circuit (not depicted in FIG. 4). Likewise, thesecond exchanger 240 has, passing through it, a stream of air conveyedby a fan. All or some of this air stream also passes through anotherheat exchanger of the engine cooling circuit (not depicted in FIG. 4).The direction in which the air flows is dependent on the mode ofoperation of the loop 210 and on the engine requirements. By way ofexample, when the combustion engine is idle and the loop 210 is in heatpump mode, the air may be heated by the heat exchanger of the enginecooling circuit and then blown onto the heat exchanger 220 to acceleratethe evaporation of fluid of the loop 210 and improve the performance ofthis loop. The heat exchangers of the cooling circuit may be activatedby valves according to engine requirements, such as, heating of the airentering the engine or putting the energy produced by this engine toproductive use.

The heat exchanger 280 may also be activated according to energyrequirements, whether this is in refrigeration mode or in heat pumpmode. Shut-off valves 290 can be installed on the branch 270 to activateor deactivate this branch.

A stream of air conveyed by a fan passes through the heat exchanger 280.This same air stream may pass through another heat exchanger of theengine cooling circuit and also through other heat exchangers placed inthe exhaust gas circuit, on the engine air inlet or on the battery inthe case of hybrid motorcars.

In the embodiment of FIG. 5, a refrigeration system 300 having arefrigeration loop 310 comprises a first heat exchanger 320, a pressureregulator 330, a second heat exchanger 340, a compressor 350 and afour-way valve 360. The first and second heat exchangers 320 and 340 areof the air/refrigerant type. The way in which the heat exchangers 320and 340 operate is the same as in the first embodiment depicted in FIG.6. Two fluid/liquid heat exchangers 370 and 380 are installed both onthe refrigeration loop circuit 310 and on the engine cooling circuit oron a secondary glycol-water circuit. Installing fluid/liquid heatexchangers without going through an intermediate gaseous fluid (air)contributes to improving heat exchange by comparison with air/fluid heatexchangers.

In the embodiment of FIG. 6, a refrigeration system 400 having arefrigeration loop 410 comprises a first series of heat exchangers 420and 430, a pressure regulator 440, a second series of heat exchangers450 and 460, a compressor 470 and a four-way valve 480. A branch-off 490mounted, on the one hand, at the exit of the heat exchanger 420 and, onthe other hand, at the exit of the heat exchanger 460, when consideringthe circulation of the fluid in refrigerant mode. This branch comprisesa heat exchanger 500 through which there passes a stream of air or astream of exhaust gases intended to be admitted to a combustion engineand a pressure regulator 510.

The heat exchangers 420 and 450 are of the air/refrigerant type and theheat exchangers 430 and 460 are of the liquid/refrigerant type. The wayin which these heat exchangers work is the same as in the thirdembodiment depicted in FIG. 5.

EXAMPLES Thermodynamic Modeling Comparison for the Heat Pump SystemsHeating Mode: Propylene

A thermodynamic modeling program, Thermocycle 3.0, was used to model theexpected performance of the blend versus HFO-1234yf./Propylene comparedto HFO-1234yf Model conditions used for the heating mode are as follows,where heat exchanger #2 was varied in 10° C. increments:

Heating Cycle Modeling Conditions Heat Exchanger #1- Inside VehicleCabin 50° C. Heat Exchange #2- Outside Air (Ambient Air Temp) −30° C. to10° C. Return Gas Heated 10° C. Compressor Efficiency 70%

Modeling results for HFO-1234yf/Propylene ranging from 1 wt % to 10 wt%.

TABLE 4 Heat Exchanger #2 = −30° C. Relative Relative CompressorCompressor Compressor Compressor (%) (%) Inlet Disc Inlet DiscCompressor Heating Heating Heating Ave Temp Temp Pres Pres DischargeCapacity Capacity vs COP COP vs Glide Refrigerant (° C.) (° C.) (kPa)(kPa) Ratio (kJ/m3) R-1234yf Heating R-1234yf (K) R-1234yf −20 74.8 98.31299.7 13.2 831.6 100.0 2.18 100.0 R-1234yf −20 76.0 101.2 1344.0 13.3855.9 102.9 2.17 99.5 0.37 (99%)/R-1270 (1%) R-1234yf −20 79.7 113.41500.6 13.2 949.1 114.1 2.15 98.6 1.09 (95%)/R-1270 (5%) R-1234yf −2082.9 129.5 1659.5 12.8 1060.2 127.5 2.12 97.2 0.99 (90%)/R-1270 (10%)

TABLE 5 Heat Exchanger #2 = −20° C. Relative Relative CompressorCompressor Compressor Compressor (%) (%) Inlet Disc Inlet DiscCompressor Heating Heating Heating Ave Temp Temp Pres Pres DischargeCapacity Capacity vs COP COP vs Glide Refrigerant (° C.) (° C.) (kPa)(kPa) Ratio (kJ/m3) R-1234yf Heating R-1234yf (K) R-1234yf −10 71.2149.9 1299.7 8.7 1204.9 100.0 2.53 100.0 R-1234yf −10 72.2 154.5 1344.08.7 1239.6 102.9 2.52 99.6 0.34 (99%)/R-1270 (1%) R-1234yf −10 75.4173.2 1500.6 8.7 1371.3 113.8 2.49 98.4 0.96 (95%)/R-1270 (5%) R-1234yf−10 78.1 197.2 1659.5 8.4 1524.0 126.5 2.46 97.2 0.80 (90%)/R-1270 (10%)

TABLE 6 Heat Exchanger #2 = −10° C. Relative Relative CompressorCompressor Compressor Compressor (%) (%) Inlet Disc Inlet DiscCompressor Heating Heating Heating Ave Temp Temp Pres Pres DischargeCapacity Capacity vs COP COP vs Glide Refrigerant (° C.) (° C.) (kPa)(kPa) Ratio (kJ/m3) R-1234yf Heating R-1234yf (K) R-1234yf 0 68.4 220.51299.7 5.9 1699.1 100.0 3.00 100.0 R-1234yf 0 69.3 227.3 1344.0 5.91747.6 102.9 2.99 99.7 0.30 (99%)/R-1270 (1%) R-1234yf 0 72.0 254.81500.6 5.9 1928.9 113.5 2.95 98.3 0.81 (95%)/R-1270 (5%) R-1234yf 0 74.2289.4 1659.5 5.7 2132.4 125.5 2.91 97.0 0.61 (90%)/R-1270 (10%)

TABLE 7 Heat Exchanger #2 = 0° C. Relative Relative CompressorCompressor Compressor Compressor (%) (%) Inlet Disc Inlet DiscCompressor Heating Heating Heating Ave Temp Temp Pres Pres DischargeCapacity Capacity vs COP COP vs Glide Refrigerant (° C.) (° C.) (kPa)(kPa) Ratio (kJ/m3) R-1234yf Heating R-1234yf (K) R-1234yf 10 66.2 314.21299.7 4.1 2342.3 100.0 3.68 100.0 R-1234yf 10 67.0 324.0 1344.0 4.12408.8 102.8 3.66 99.5 0.26 (99%)/R-1270 (1%) R-1234yf 10 69.2 363.21500.6 4.1 2653.1 113.3 3.61 98.1 0.67 (95%)/R-1270 (5%) R-1234yf 1071.0 410.9 1659.5 4.0 2917.0 124.5 3.56 96.7 0.43 (90%)/R-1270 (10%)

TABLE 8 Heat Exchanger #2 = 10° C. Relative Relative CompressorCompressor Compressor Compressor (%) (%) Inlet Disc Inlet DiscCompressor Heating Heating Heating Ave Temp Temp Pres Pres DischargeCapacity Capacity vs COP COP vs Glide Refrigerant (° C.) (° C.) (kPa)(kPa) Ratio (kJ/m3) R-1234yf Heating R-1234yf (K) R-1234yf 20 64.5 435.51299.7 3.0 3168.1 100.0 4.70 100.0 R-1234yf 20 65.1 449.3 1344.0 3.03257.9 102.8 4.68 99.6 0.22 (99%)/R-1270 (1%) R-1234yf 20 78.1 503.61500.6 3.0 3693.6 116.6 4.72 100.4 0.52 (95%)/R-1270 (5%) R-1234yf 2068.3 567.3 1659.5 2.9 3915.8 123.6 4.55 96.8 0.29 (90%)/R-1270 (10%)

Modeling results show that blends of HFO-1234yf with R-1270 from 1 wt %to 10 wt % provide a significant advantage over neat HFO-1234yf. At −30°C. ambient temperatures, HFO-1234yf alone does not perform well. Thecompressor inlet pressure is sub-atmospheric and air would be pulledinto the compressor (tables 4). Therefore, HFO-1234yf is limited for useas a heat pump fluid to −20° C. without some sort of system redesign.However, even 1 wt % R-1270 (propylene) significantly improves theperformance of the resultant blend with HFO-1234yf (99 wt %)/R-1270 (1wt %) being able to operate at temperatures down to −30° C. Therefore,the inventive blends of HFO-1234yf/R-1270 extend the heating range by adelta of at least 10° C.

Blends of HFO-1234yf with R-1270 (propylene) from 1 wt % to 10 wt % alsoprovide a significant advantage over neat HFO-1234yf in terms ofimproved heating capacity. Modeling results show that even 1 wt % ofR-1270 has over 2.9% heat capacity improvement while up to 10% propylenecan significantly improve the relative heat capacity up to 27.5%. Theimproved heating capacity of the inventive blends shows that the newfluids can easily be used to provide adequate heat to a passenger cabin.Additionally, the resultant inventive blends generally have a similar orreduced compressor discharge ratio versus neat HFO-2134yf over the heatpump operating range.

Modeling shows that blends of HFO-1234yf and R-1270 (propylene) from 1wt % to 5 wt % have similar COP or energy performance in the heatingrange of −30° C. to +10° C. Blends of HFO-1234yf and R-1270 (propylene)from >5 wt % up to 10 wt % have adequate COP in the heating range.

Additionally, blends which contain 1 to 10 wt % R-1270 (propylene) alsoexhibit near negligible glide over the desired heating range, i.e., from−30° C. up to 10° C. Therefore, the R-1270 blends have extremelyfavorable glide and can be serviced as near azeotropic blends over theentire heating range without limitation.

Therefore, the HFO-1234yf/R-1270 refrigerant blends noted hereinuniquely provide improved capacity 2.9% to 27% over HFO-1234yf in theheating operating range from −30° C. to +10° C., extend the lowerheating range capability over HFO-1234yf by a delta of 10° C., haveextremely low GWP (less than 10) and low to mild flammability (class 2to class 2L), while also uniquely exhibiting nearly negligible glideover heating range for servicing.

While all blends of HFO-1234yf and R-1270 would be desirable, thepreferred blends with advantageous flammability for a heat pump fluidare 99 wt % HFO-1234yf to 76.2 wt % HFO-1234yf and 1 wt % R-1270 to 23.8wt % R-1270, with more preferred blends being 99 wt % HFO-1234yf to 90wt % HFO-1234yf and 1 wt % to 10 wt % R-1270 and most preferred blendbeing 99% HFO-1234yf to 93 wt % HFO-1234yf and 1 wt % R-1270 to 7 wt %R-1270.

Thermodynamic Modeling Comparison for the Heat Pump Systems CoolingMode: Propylene

A thermodynamic modeling program, Thermocycle 3.0, was used to model theexpected performance of the blend versus HFO-1234yf compared toHFO-1234yf/Propylene. Model conditions used for the cooling mode are asfollows, where heat exchanger #2 was varied in 10 C increments:

Modeling Conditions Heat Exchanger #1- Inside Cabin 0° C. Heat Exchange#2- Outside Air (Ambient Air Temp) 20° C. to 40° C.

TABLE 9 Heat Exchanger #2 T = 20° C. Relative Compr CompressorCompressor Compressor (%) Relative Inlet Disc Inlet Disc CompressorCooling Cooling Cooling Ave Temp Temp Pres Pres Discharge Capacity Capvs COP COP vs Glide Refrigerant (° C.) (° C.) (kPa) (kPa) Ratio (kJ/m3)R-1234yf Cooling R-1234yf (K) R-1234yf 10 33.7 314.2 589.3 1.9 2437.2100.0 8.58 100.0 R-1234yf 10 34.1 327.2 615.2 1.9 2532.2 103.9 8.53 99.40.20 (99%)/Propylene (1%) R-1234yf 10 35.0 376.2 703.7 1.9 2865.2 117.68.47 98.7 0.38 (95%)/Propylene (5%) R-1234yf 10 35.3 428.7 789.4 1.83181.2 130.5 8.46 98.6 0.14 (90%)/Propylene (10%)

TABLE 10 Heat Exchanger #2 T = 30° C. Relative Compr CompressorCompressor Compressor (%) Relative Inlet Disc Inlet Disc CompressorCooling Cooling Cooling Ave Temp Temp Pres Pres Discharge Capacity Capvs COP COP vs Glide Refrigerant (° C.) (° C.) (kPa) (kPa) Ratio (kJ/m3)R-1234yf Cooling R-1234yf (K) R-1234yf 10 44.8 314.2 780.8 2.5 2204.46100.0 5.36 100.0 R-1234yf 10 45.4 325.9 812.2 2.5 2279.9 103.4 5.33 99.40.24 (99%)/Propylene (1%) R-1234yf 10 46.7 371.3 920.5 2.5 2552.4 115.85.27 98.3 0.51 (95%)/Propylene (5%) R-1234yf 10 47.6 422.8 1027.4 2.42827.8 128.3 5.25 97.9 0.24 (90%)/Propylene (10%)

TABLE 11 Heat Exchanger #2 T = 40° C. Relative Compr CompressorCompressor Compressor (%) Relative Inlet Disc Inlet Disc CompressorCooling Cooling Cooling Ave Temp Temp Pres Pres Discharge Capacity Capvs COP COP vs Glide Refrigerant (° C.) (° C.) (kPa) (kPa) Ratio (kJ/m3)R-1234yf Cooling R-1234yf (K) R-1234yf 10 55.6 314.2 1015.6 3.2 1961.5100.0 3.71 100.0 R-1234yf 10 56.3 324.8 1053.1 3.2 2020.8 103.0 3.6999.5 0.26 (99%)/R-1270(1%) R-1234yf 10 58.1 367.0 1184.1 3.2 2238.4114.1 3.63 97.8 0.61 (95%)/R-1270 (5%) R-1234yf 10 59.4 416.8 1315.3 3.22468.1 125.8 3.60 97.0 0.34 (90%)/R-1270(10%)

For any heat pump fluid to be a viable candidate, it needs to alsoperform well in the cooling mode, i.e. in higher ambient temperatures itneeds to provide adequate cooling. Modeling results show that blends ofHFO-1234yf with R-1270 from 1 wt % to 10 wt % provide a significantadvantage over neat HFO-1234yf in the cooling range from 20° C. up to40° C. ambient.

Blends of HFO-1234yf with R-1270 (propylene) from 1 wt % to 10 wt % alsoprovide a significant advantage over neat HFO-1234yf in terms ofimproved cooling capacity. Modeling results show that even 1 wt % ofR-1270 has over 2% heat capacity improvement while up to 10% propylenecan significantly improve the relative cooling capacity up to 22%. Theimproved cooling capacity of the inventive blends shows that the newfluids can easily be used to provide adequate cooling (air-conditioning)to a passenger cabin. Additionally, the resultant inventive blendsgenerally have a similar compressor discharge ratio versus neatHFO-2134yf over the cooling operating range.

Modeling shows that blends of HFO-1234yf and R-1270 (propylene) from 1wt % to 10 wt % have similar COP or energy performance in the coolingrange from +20° C. to +40° C.

Additionally, blends which contain 1 to 10 wt % R-1270 (propylene) alsoexhibit negligible glide over the desired cooling range, i.e., from +20°C. to +40° C. Therefore, this inventive blend can be serviced in almostany ambient environment.

Therefore, the HFO-1234yf/R-1270 refrigerant blends noted hereinuniquely provide improved capacity 2% to 22% over HFO-1234yf in thecooling operating range from +20 to +40 C, have extremely low GWP (lessthan 10) and low to mild flammability (class 2 to class 2L), while alsouniquely exhibiting nearly negligible glide for all heat pump operatingtemperatures.

While all blends of HFO-1234yf and R-1270 would be desirable, thepreferred blends with advantageous flammability for a heat pump (i.e.operating in the heating or cooling mode) fluid are 99 wt % HFO-1234yfto 78 wt % HFO-1234yf and 1 wt % R-1270 to 22 wt % R-1270, with morepreferred blends being 99 wt % HFO-1234yf to 80 wt % HFO-1234yf and 1 wt% to 20 wt % R-1270 and most preferred blend being 99% HFO-1234yf to 90wt % HFO-1234yf and 1 wt % R-1270 to 10 wt % R-1270.

While the invention has been described with reference to a preferredembodiment, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment disclosed as the best modecontemplated for carrying out this invention, but that the inventionwill include all embodiments falling within the scope of the appendedclaims.

What is claimed is:
 1. A refrigerant composition comprising:2,3,3,3-tetrafluoropropene (HFO-1234yf) and propylene (R-1270); whereinthe composition is near-azeotropic.
 2. The composition of claim 1:wherein the composition is azeotrope-like.
 3. The composition of claim1: wherein the 2,3,3,3-tetrafluoropropene (HFO-1234yf) concentration isgreater than or equal to the 2,3,3,3-tetrafluoropropene (HFO-1234yf)concentration of a propylene NAL1; and wherein the2,3,3,3-tetrafluoropropene (HFO-1234yf) concentration is less than orequal to the 2,3,3,3-tetrafluoropropene (HFO-1234yf) concentration of apropylene NAH1.
 4. The composition of claim 1: wherein the2,3,3,3-tetrafluoropropene (HFO-1234yf) concentration is greater than orequal to the 2,3,3,3-tetrafluoropropene (HFO-1234yf) concentration of apropylene ALL1; and wherein the 2,3,3,3-tetrafluoropropene (HFO-1234yf)concentration is less than or equal to the 2,3,3,3-tetrafluoropropene(HFO-1234yf) concentration of a propylene ALH1.
 5. The composition ofclaim 1: wherein the propylene (R-1270) is present in an amount up to 24weight percent, based on the total refrigerant composition.
 6. Thecomposition of claim 5, wherein the propylene (R-1270) is from 1 to 20weight percent based on the total refrigerant composition.
 7. Thecomposition of claim 6, wherein the propylene (R-1270) is present in anamount from 1 to 10 weight percent based on the total refrigerantcomposition.
 8. The composition of claim 7, wherein the propylene(R-1270) is present in an amount from 1 to 7 weight percent based on thetotal refrigerant composition.
 9. The composition of claim 8, whereinthe composition exhibits near azeotropic properties over the temperaturerange of −30° C. to 40° C.
 10. The composition of claim 9, wherein therefrigerant composition is a heat pump fluid.
 11. The composition ofclaim 1, wherein the heat capacity of the refrigerant composition isbetween 2.9% and 27.5% greater than the heat capacity of2,3,3,3-tetrafluoropropene (HFO-1234yf) alone.
 12. The composition ofclaim 1, wherein the heat capacity of the refrigerant composition isbetween 2% and 22% greater than the heat capacity of2,3,3,3-tetrafluoropropene (HFO-1234yf) alone.
 13. The composition ofclaim 1, wherein the GWP of the refrigerant composition is less than 10.14. The composition of claim 1, wherein the refrigerant composition hasa temperature glide of less than 1.1 Kelvin (K) at temperature of −30°C. up to 10° C.
 15. The composition of claim 1: wherein a ratio of aheat capacity of the composition of claim 1 to a heat capacity of2,3,3,3-tetrafluoropropene (HFO-1234yf) is between 1.05 and 1.50 at thesame temperature and pressure.
 16. A heating or cooling systemcomprising, in a serial arrangement: a condenser; an evaporator; and acompressor, the system further comprising each of the condenser,evaporator and compressor operably connected, the refrigerantcomposition of claim 1 being circulated through each of the condenser,evaporator and compressor.
 17. The heating or cooling system of claim16: wherein the system is an air conditioner for an automotive system.18. The heating or cooling system of claim 16: wherein the system is anair conditioner for a stationary cooling system.
 19. The heating orcooling system of claim 16: further comprising a 4-way valve.
 20. Theheating or cooling system of claim 16: wherein the system is a heat pumpfor an automotive system.
 21. The refrigeration system of claim 16:wherein the system is heat pump for a residential heating or coolingsystem.
 22. The refrigeration system of claim 21: wherein a temperatureglide is less than 1.1 Kelvin (K).
 23. The use of the refrigerantcomposition of claim 1 in a heat pump system.
 24. The use of therefrigerant composition of claim 1 in an HEV, MHEV, PHEV, or EV heatpump system.
 25. The use of the refrigerant composition of claim 1 in anHEV, MHEV, PHEV, or EV heat pump system in combination with a vehicleelectrical system.
 26. A method of charging a refrigerant composition toan automotive system comprising: providing the composition of claim 1 toan automotive heating or cooling system.
 27. A method for improvinggross contaminants from a refrigerant composition comprising: providinga first refrigerant composition; wherein the first refrigerantcomposition is not near azeotropic and includes2,3,3,3-tetrafluoropropene (HFO-1234yf) and at least one of ethane(R-170) or propane (R-290); providing at least one of2,3,3,3-tetrafluoropropene (HFO-1234yf), ethane (R-170) or propane(R-290) to the first refrigerant composition to form a secondrefrigerant composition; wherein the second refrigerant composition isnear-azeotropic.
 28. The method of claim 23, wherein the secondrefrigerant composition is formed from the first refrigerant compositionwithout the use of conventional onsite automatic recovery, recycle,recharge equipment.